David Cameron angered some in his party on Wednesday when he said the storms and floods causing havoc across Britain could have been caused by climate change.

During his weekly questions in the Commons, the prime minister said he suspected global warming could be responsible for an increase in extreme weather events, including recent storms that have left seven dead and hundreds of homes inundated.

Warning of more stormy weather to come he urged people to remain on alert in regions due for more heavy rain this Wednesday and Thursday.

Experts, including Sir David King, the government's climate change representative, have warned that spending on flood defences needs to double by 2020 as global warming could be increasing the risk of extreme weather.

To a backdrop of groans from Conservative MPs, Cameron told the Commons he did believe Britain was getting "more abnormal weather events", which could be linked to climate change.

A number of Tories are sceptical about the science of climate change or the effectiveness of measures to tackle it. They include the environment secretary, Owen Paterson, who has suggested that global warming could be beneficial to the UK.

The prime minister said: "Colleagues across the house can argue about whether that is linked to climate change or not. I very much suspect that it is. The point is that whatever one's view it makes sense to invest in flood defences … it makes sense to get information out better, and we should do all of those things."

Cameron was pressed on the subject by Ed Miliband. The Labour leader demanded a full report on flooding, climate change and the UK's weather defences.

Miliband said: "Given the scale of risk exposed by these floods and the expected impact of climate change, can you commit to the Department for Environment, Food and Rural Affairs providing a report to this house by the end of this month giving a full assessment of the future capability of our flood defences and flood response agencies, and whether the investment plans in place are equal to the need for events of this kind?"

Cameron said he was happy for Paterson to provide a report on all those issues. "Whenever there is flooding it then makes sense to look again at the proposals that are in the programme for flood defence work to see what more can be done."

Labour also questioned the government's claim that a record amount would be spent on flood defences in the period between 2011 and 2015. Official figures show government spending on flood defences has fallen during this period.

However, Cameron, while claiming that more money than ever will be spent on the defences, has been including the cash likely to come from the private sector.

"As well as the government money we are keen to lever in more private-sector and local authority money, which is now possible under the arrangements, but I am happy to commit for the environment secretary to come back and report to the house about the level of expenditure in the years going ahead," he said.

Ed Davey, secretary of state for energy and climate change, is meanwhile preparing to meet the directors of power companies, following criticism about their slow response to electricity blackouts caused by storms.

Cameron told the Commons that the network companies could have been better prepared.

"On the positive side the Environment Agency warning service worked better than it has in the past. The flood defences did protect up to a million homes over the December and Christmas period," Cameron said.

"But there are some negatives there and we need to learn lessons. Particularly, some of the energy companies did not have enough people over the holiday period for emergency response. I saw that for myself in Kent. So we need to learn those lessons."